Alte Lansing VS2621s. picked em up for about £50. i listen to Drum & Bass, Dubstep, Metal and so on as well as mixing on them, and they perform very solidly at the bottom end.
My particular pair are not brilliantly shielded, but they really vibrate the walls when Skrillex or Dubba Jonny bring in a drop and its up full blast. thats pretty outstanding for low powered speakers.